There are presently available a number of different types of oscillating fan arrangements. According to the most popular type, the fan comprises a swivel type housing having a plurality of fan blades fixed within the housing. This particular type of oscillating fan requires a very substantial and powerful oscillation mechanism in order to rotate the entire housing of the fan. Furthermore, due to the amount of work required to move the entire housing, there is generally a heavy drain on the fan motor.
There are a number of less well known oscillating fan arrangements in which the fan housing remains stationary, while the vanes of the fan oscillate relative to the housing. However, according to most of these arrangements there is either a two motor system in which one motor is used to drive the fan blade and the second motor is used to drive the oscillating vanes, as described in U.S. Pat. No. 4,084,491 issued Apr. 18, 1978 to Spotts et al or there is a fixed connection between the vanes and the fan motor, so that the fan blade and the vanes cannot be controlled independently of one another as described in U.S. Pat. No. 1,861,608 issued June 7, 1932 to L. M. Persons.
A more unique oscillating fan is described in U.S. Pat. No. 2,768,782 issued Oct. 30, 1956 to A. K. Tateishi. According to this latter patent, an electric fan is provided in which the fan motor is used to operate both the fan blade and the vanes which are adapted to oscillate relative to the fan housing. A single rotational control member is used to operate both the motor and the oscillating vanes. The motor is turned on through an initial rotation of the control member and further rotation of the control member is required to cause the vanes to oscillate. With this single control there is an initial slippage of the drive system as it is gradually moved into an operative position in order to free the motor to reach maximum rpm's. However if the control member is not properly adjusted after the motor reaches maximum rpm, the slippage will continue resulting in inefficient operation of the oscillating vanes and possible wear on the components in the drive system. Furthermore the arrangement is relatively complicated, since a single control member is used to rotationally adjust both the on/off switching of the fan and the incremental adjustment of the drive system which is in itself quite complex. This drive system includes a crank and rocker arrangement requiring numerous components and connections to the vanes in order to produce vane oscillation making the system obsolete from a cost standpoint.
An additional drawback of the earlier Tateishi patent is that, the drive system may be adjusted to the extent that it is effectively locked in a non-slip position via the control member which is not desirable in the event that the vanes become jammed putting undue pressure on the drive system resulting in wear and damage to both the drive system and the fan motor.